CONTROL OF CELLULASE ACTIVITY BY INDOLEACETIC ACID

1966 ◽  
Vol 44 (8) ◽  
pp. 1025-1034 ◽  
Author(s):  
Der-Fong Fan ◽  
G. A. Maclachlan
Keyword(s):  
Protein Synthesis ◽  
Soluble Protein ◽  
Indoleacetic Acid ◽  
Cellulase Activity ◽  
Growth Responses ◽  
Pea Seedlings ◽  
Auxin Concentration ◽  
Lateral Cell ◽  
Main Growth

Apices of etiolated decapitated Alaska pea seedlings were painted with aqueous lanolin + IAA ± various inhibitors of RNA or protein synthesis. A subapical segment from the epicotyl was removed for measurements of growth and the soluble protein content and cellulase activity of enzyme extracts.During the first 18 hours, the main growth response to IAA was an increase in segment diameter; elongation was inhibited. The amount of extractable cellulase activity per segment and the diameter increased at exactly the same rates relative to controls. In the next 2 days IAA induced rapid cell division and the formation of root primordia. Cellulase activity per segment, per unit fresh weight, and per unit soluble protein all increased markedly to levels many times higher than in controls. Chloramphenicol, azaguanine, puromycin, and actinomycin D all interfered with protein synthesis, the growth responses, and the development of cellulase activity. In the absence of IAA, cellulase activity decreased.It is concluded that cellulase is subject to turnover in this tissue and that the rate of its synthesis is controlled by auxin concentration. It is proposed that cellulase action on microfibrils in vivo plays an essential role in a variety of growth processes, particularly lateral cell expansion.

Protein synthesis in pulmonary arteries from rats exposed to hyperoxia

1993 ◽  
Vol 264 (1) ◽  
pp. L74-L79
Author(s):  
W. S. Stirewalt ◽  
J. T. Coflesky ◽  
L. H. Young ◽  
J. N. Evans
Keyword(s):  
Protein Synthesis ◽  
Soluble Protein ◽  
Growth Response ◽  
Pulmonary Arteries ◽  
Protein Fractions ◽  
Tissue Protein ◽  
Fractional Rate ◽  
Fractional Synthesis

These studies were undertaken to determine the relationship of early changes in the synthesis rates and contents of collagen, elastin, and soluble tissue protein of pulmonary arteries in rats exposed chronically to normobaric hyperoxia. The growth response of pulmonary arteries was characterized by proportionate increases in the contents of the three protein fractions after 7 days (130% of control) and 21 days (194% of control) of exposure. Fractional rates of protein synthesis were assessed both in vivo and in vitro with the use of several radiolabeled amino acids as tracers to minimize uncertainties of the relationships of the specific radioactivities of measured amino acid pools and the precursors for the proteins fractions. Values for fractional synthesis rates of collagen, elastin, and soluble protein in vitro in pulmonary arteries isolated from control rats were 2.2, 1.6, and 19%/day, respectively. Rates of synthesis of collagen and soluble protein in vitro were approximately 20% lower than that determined in control rats in vivo. The fractional synthesis rates of the three protein fractions in isolated arteries from experimental rats were unchanged after 1 day of hyperoxic exposure, decreased marginally after 3 days, and markedly increased after 7 days. At this time the absolute increments in the fractional synthesis rates of collagen (+4.7%/day) and elastin (+5.0%/day) were less than that of soluble tissue protein (+16%/day) and were more comparable to the accumulation rate of proteins in the tissue. The disproportionate increment in the fractional rate of soluble protein synthesis suggests that the fractional rate of degradation of soluble protein was also increased during the growth response in this model of hypertension.

STUDIES ON THE REGULATION OF CELLULASE ACTIVITY AND GROWTH IN EXCISED PEA EPICOTYL SECTIONS

1967 ◽  
Vol 45 (10) ◽  
pp. 1837-1844 ◽  
Author(s):  
Der-Fong Fan ◽  
G. A. Maclachlan
Keyword(s):  
Turnover Rate ◽  
Actinomycin D ◽  
Indoleacetic Acid ◽  
Specific Activity ◽  
Cellulase Activity ◽  
Pisum Sativum L ◽  
Pea Epicotyl ◽  
D 20

Applied indoleacetic acid (10−4 – 10−6 M) increased elongation and the amount and specific activity of cellulase in sections detached from the epicotyl of Pisum sativum L. var. Alaska. Actinomycin D (20 μg/ml) inhibited growth and the capacity of sections for synthesizing protein from absorbed 14C-leucine. At the same time it caused cellulase levels to decrease at a rate which indicated a half-life for the enzyme of less than 24 h. Pea cellulase was most stable in vitro between pH 6 and 7; at or below pH 5 its rate of denaturation was comparable to its turnover rate in vivo. Fractionation of sections yielded wall preparations which contained cellulase at a higher specific activity than particles or supernatant. It is concluded that cellulase is synthesized in excised sections by an auxin-regulated mechanism. It is proposed that the enzyme is transported to the wall where it may promote elongation and eventually become denatured.

Respiratory energy requirements and rate of protein turnover in vivo determined by the use of an inhibitor of protein synthesis and a probe to assess its effect

1994 ◽  
Vol 92 (4) ◽  
pp. 585-594 ◽  
Author(s):  
T. J. Bouma ◽  
R. De Visser ◽  
J. H. J. A. Janssen ◽  
M. J. De Kock ◽  
P H. Van Leeuwen ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Energy Requirements ◽  
Inhibitor Of Protein Synthesis

Rapid in vivo induction of leukocyte tissue factor mRNA and protein synthesis following low dose endotoxin administration to rabbits

2001 ◽  
Vol 2 (3) ◽  
pp. 188-195 ◽  
Author(s):  
Tara C Brutzki ◽  
Myron J Kulczycky ◽  
Leslie Bardossy ◽  
Bryan J Clarke ◽  
Morris A Blajchman
Keyword(s):  
Protein Synthesis ◽  
Tissue Factor ◽  
Low Dose ◽  
Endotoxin Administration ◽  
In Vivo Induction

scholarly journals LOCALIZED MUTAGENESIS FOR THE ISOLATION OF TEMPERATURE-SENSITIVE MUTANTS OF ESCHERICHIA COLI AFFECTED IN PROTEIN SYNTHESIS

Genetics ◽  
1979 ◽  
Vol 91 (2) ◽  
pp. 215-227
Author(s):  
W Scott Champney
Keyword(s):  
Escherichia Coli ◽  
Protein Synthesis ◽  
Temperature Sensitive ◽  
Chromosomal Locus ◽  
Ribosomal Subunits ◽  
Prolonged Incubation ◽  
Temperature Sensitive Mutants ◽  
Inhibition Of Growth ◽  
Localized Mutagenesis

ABSTRACT Two variations of the method of localized mutagenesis were used to introduce mutations into the 72 min region of the Escherichia coli chromosome. Twenty temperature-sensitive mutants, with linkage to markers in this region, have been examined. Each strain showed an inhibition of growth in liquid medium at 44°, and 19 of the mutants lost viability upon prolonged incubation at this temperature. A reduction in the rate of in vivo RNA and protein synthesis was observed for each mutant at 44°, relative to a control strain. Eleven of the mutants were altered in growth sensitivity or resistance to one or more of three ribosomal antibiotics. The incomplete assembly of ribosomal subunits was detected in nine strains grown at 44°. The characteristics of these mutants suggest that many of them are altered in genes for translational or transcriptional components, consistent with the clustering of these genes at this chromosomal locus.

scholarly journals Comprehensive assessment of post-prandial protein handling by the application of intrinsically labelled protein in vivo in human subjects

2021 ◽  
pp. 1-9
Author(s):  
Jorn Trommelen ◽  
Andrew M. Holwerda ◽  
Philippe J. M. Pinckaers ◽  
Luc J. C. van Loon
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Stable Isotope ◽  
Dietary Protein ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Human Subjects ◽  
Whole Body ◽  
Body Protein

All human tissues are in a constant state of remodelling, regulated by the balance between tissue protein synthesis and breakdown rates. It has been well-established that protein ingestion stimulates skeletal muscle and whole-body protein synthesis. Stable isotope-labelled amino acid methodologies are commonly applied to assess the various aspects of protein metabolism in vivo in human subjects. However, to achieve a more comprehensive assessment of post-prandial protein handling in vivo in human subjects, intravenous stable isotope-labelled amino acid infusions can be combined with the ingestion of intrinsically labelled protein and the collection of blood and muscle tissue samples. The combined application of ingesting intrinsically labelled protein with continuous intravenous stable isotope-labelled amino acid infusion allows the simultaneous assessment of protein digestion and amino acid absorption kinetics (e.g. release of dietary protein-derived amino acids into the circulation), whole-body protein metabolism (whole-body protein synthesis, breakdown and oxidation rates and net protein balance) and skeletal muscle metabolism (muscle protein fractional synthesis rates and dietary protein-derived amino acid incorporation into muscle protein). The purpose of this review is to provide an overview of the various aspects of post-prandial protein handling and metabolism with a focus on insights obtained from studies that have applied intrinsically labelled protein under a variety of conditions in different populations.

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